Prognosis for children with Autism Spectrum Disorder (ASD) receiving intensive early intervention has improved substantially. A minority of these children appear to reach what may be called "optimal outcome", in which cognitive and adaptive functioning are within normal limits and they no longer meet criteria for any ASD. Little or no rigorous documentation of such children or their status has been attempted and some recent papers have suggested that such an outcome is not a realistic aim for ASD children; therefore, even the existence of the optimal outcome group remains controversial. None of these children has been studied in detail, or followed into adolescence, so the extent to which their functioning has truly normalized is not known. Since language difficulties in ASD are so pervasive and central, residual language difficulties might be expected to persist even in children with optimal outcomes. Preliminary studies on a group of such children suggest that they show many areas of normalized language functioning as well as specific areas in which impairment is still demonstrated. We propose to study a group of these children in early to mid- adolescence and fully assess their language, cognitive, and adaptive competence. One important question naturally arises from our preliminary results: what are the underlying neural mechanisms of the striking improvement of cognitive processes in these optimal outcome children? It could be hypothesized that their atypical acquisition of early language resulted in an atypical neural representation of language processes, even with normal behavioral performance. This would imply that alternative neural pathways and networks may be recruited to perform a task to behaviorally normal levels, suggesting the existence of multiple developmental pathways to successful functioning. On the other hand, the optimal outcome children with normal performance levels might show typical patterns of brain activation, suggesting that only remediation that normalizes the use of neural networks can result in normal task performance; this would have implications for the importance of very early intervention. fMRI tasks of syntax and face processing will be administered to address this question, and exploratory analysis of selected structural variables will be examined to see if the most successful intervention appears to operate on a structurally normal brain. [unreadable] [unreadable] [unreadable]